The present invention relates to a method and a device for charging a battery of an electric drive using components of the electric drive.
Electric drives are frequently supplied with energy by batteries or accumulators. Such batteries typically provide a DC voltage, which are frequently converted into an AC voltage with the aid of a drive converter or a DC/AC converter for operating the electric drive. The electric drive then converts the electric energy, for example, into a rotary motion or the like.
To charge these batteries, charging devices are often used which are independent of the drive and are implemented with the aid of separate electrical components. In electrically driven vehicles, the charging devices are often integrated into the vehicles in such a way that the vehicles must simply be connected to an electrical power supply network with the aid of electrical plug connections or the like. The bulk of the charging electronics is thus, for example, integrated into the vehicle.
If an AC voltage is provided by the power supply network, this AC voltage must be converted by the charging device into a DC voltage which is suitable for charging the battery. To implement charging devices of this kind, multistage circuit structures are therefore often used which, for example, may include a line filter, a step-down converter, an intermediate circuit, and a step-up converter.
In this context, when implementing a battery charging device, it is known from the publication WO 2010/103063 A1 to use the drive converter of the electric drive instead of a step-up converter provided specifically for the charging device, and to use the inductors of the electrical motor instead of an intermediate storage provided specifically for the charging device.